I was on the fence about getting the Kreg Jig Master System or the more expensive Kreg Toolboxx Master Collection. It took me quite a while to find out all the differences, so I'm writing this review to help any others. I was leaning toward getting the less-expensive Master System and did not think I would be able to justify the more expensive Toolbox Master Collection. After breaking it all out and considering what you get, I went with the Toolboxx Master Collection and have been happy so far. This review will focus on the differences, instead of describing all those things you get in both sets.
From what I can tell, the Toolbox Master Collection $299 has everything in Jig Master System $139 plus the following:
* Toolbox and Screw Kit $78. You are going to need screws anyway; I figured I may as well get a variety up front. Otherwise every time I have a different joint/stock I may avoid using the Kreg jig all together because I don't have the right screws. However the master collection toolbox is even better because it is deeper than the one sold separately. My father-in-law had the Master System. We used it for a project and my wife and I liked it a lot. Though there is no way to keep things organized in the case. Everything just gets stuffed in wherever it fits. However with the toolbox, there is plenty of room to grow and still keep things organized.
* Kreg Micro Jig $45. This jig uses smaller diameter holes and screws, good for light duty 1/2" stock. Be aware that the regular Kreg Jig also claims to go down to 1/2" stock. So this doesn't let you really go thinner, but just better suited for some cases.
* Kreg Jig HD $59. This jig uses larger diameter holes and screws. It can use used for 1 1/2" stock and larger (I guess up to 4x4 stock). The regular Kreg Jig goes up to 1 1/2 stock, but this HD jig is 50% stronger.
* Right-Angle Clamp $25. It should make driving right angles quick and easy, which would otherwise be hard to clamp.
* The clamping base lever is in the front instead of the back as it is in the Master System. For me this was a small bonus. It's easier to use when you have a large board (like plywood) because you don't have to reach around behind to operate. But the tradeoff is you can't put a clamp right there in the front to hold the base to your bench. Instead you can just screw it into a scrap board and then clamp that down.
* Lastly, there is a $50 rebate from the manufacturer's website if you purchase by March 31 2013.